Exception thrown when the ORB attempted to reach an object and failed.
It is not an indication that an object does not exist. Instead, it simply
means that no further determination of an object's status was possible
because it could not be reached. This exception is raised if an attempt
to establish a connection fails, for example, because the server or the
implementation repository is down.

It contains a minor code, which gives more detailed information about
what caused the exception, and a completion status. It may also contain
a string describing the exception.